CN103222164A - Brushless dc motor, and method for controlling same - Google Patents

Abstract

This brushless DC motor (1) is provided with a stator (3) having a main body (312, 322) disposed on both ends thereof in the rotational axis direction with a single exciting coil (2) disposed between the main bodies (312, 322), and with a rotor (4) disposed in the interior of the stator (3), wherein main body (312) is formed with a first magnetic core (31) and main body (322) is formed with a second magnetic core (32), the magnetic cores (31, 32) functioning as a magnetic pole and having protrusions (311, 321), the quantity of which being different for each magnetic core (31, 32). The brushless DC motor (1) uses, as the driving force, the variation in the magnetic resistance between the stator (3) and the rotor (4) in relation to the flow of the magnetic flux generated in the periphery of the exciting coil (2). The method for controlling the brushless DC motor (1) of the present invention is a method for controlling the abovementioned brushless DC motor (1) in which starting coils (5 (5a, 5b)) each having a rectifier cell (52 (52a, 52b)) are disposed on the periphery of protrusion (321), wherein the rectifier cells (52) of the starting coils (5) impart, to the exciting coil (2), a pulse current having a polarity corresponding to the intended rotational direction, and having a start-up time and wave height that are sufficient for turning on.

Description

DC brushless motor and control method thereof

Technical field

The present invention relates to a kind of DC brushless motor and control method thereof, relate generally to a kind of dust core that uses and come drive electric motor as iron core and by single-phase excitation.

Background technology

Motor utilizes in extensive fields such as motor vehicle, household electrical appliances and industrial uses as the parts that power conversions become power.Motor possesses as the fixture of non-rotating part and the revolving part that rotates with output shaft, includes solenoid, magnet, iron core in them.

Motor is divided into several kinds according to the principle or the structure that produce actuating force, the use of one of them motor of permanent magnet be called as PM (Permanent Magnet) motor, be used in special extensive fields.In this PM motor, described permanent magnet is set on revolving part, the interaction of the magnetic flux that solenoid by being located at fixture and described permanent magnet send produces revolving force.

Yet therefore motor wishes miniaturization consumingly owing to be power source, owing to its miniaturization needs to produce stronger magnetic force.In order to obtain this stronger magnetic force, need send the magnet of strong magnetic flux, for example in patent documentation 1, develop a kind of magnet (Nd that has used the element of Nd-Fe-B system; Neodymium, Fe; Iron, B; Boron).Yet these magnet need high price and the rare metal of Dy (dysprosium), Nd etc.On the other hand, also can access strong magnetic force (electromagnetic force) by increasing the magnetic field that produces by solenoid.As its gimmick, the number of turn that increases exciting current or increase solenoid is effective.Yet the former is subjected to the restriction of the sectional area of coil, and the latter is subjected to the restriction in space that winding is reeled, has the limit naturally.

Therefore, in recent years, iron core has used the exploitation of the motor of dust core constantly to make progress.Described dust core is shaped and heat treatment is shaped by press-powder after soft magnetism has formed insulating coating with the surface of powder.At this, all the time, in motor, use electromagnetic steel plate carried out stamping-out, stacked stacked magnetic core, this stacked magnetic core on stacked direction, make magnetic flux be difficult to by, and magnetic flux is passed through easily, therefore carried out the magnetic Circuit Design in the plane.With respect to this, above-mentioned dust core carries out press-powder to soft magnetism with powder and is shaped and forms, so magnetic characteristic is isotropism, can be described as the core material that can carry out three-dimensional magnetic Circuit Design.And, dust core can form shape arbitrarily by the change of the mold shape in the press-powder shaping or the machining after the shaping etc., therefore the variation of motor core shape can be realized by the magnetic design of three-dimensional, the design of platypelloid type or small-sized motor can be carried out.

Realize the motor of miniaturization as the such dust core of effective utilization, for example to patent documentation 4, disclose a kind of blade tooth (claw teeth) type motor that uses three-dimensional magnetic circuit at patent documentation 2.According to described patent documentation 2 to patent documentation 4, in the past, with regard to the structure that on each tooth, is wound with coil, adorned circular coil on the iron core of claw-pole type, thus, described disclosed claw-teeth-type motor can be realized the miniaturization that improves, promptly improve based on magnetic force based on winding density.And, by using dust core, can carry out the driving under the AC magnetic field, by being made as electric angle 120 ° the stator of three-decker that staggers mutually, and described disclosed claw-teeth-type motor also can carry out the brushless driving under the three-phase alternating current magnetic field.

On the other hand, to patent documentation 4, a kind of claw-pole motor that uses dust core is disclosed at above-mentioned patent documentation 2.And, fixture becomes the structure with three-dimensional magnetic circuit, the dust core that has pawl type magnetic pole of this three-dimensional magnetic circuit surrounds coil, but described disclosed claw-pole motor has been to use the motor of the current source of three-phase, three fixtures are arranged along the rotating shaft direction, are assigned with an electric current phase respectively.Therefore, be necessary in each single-phase three-decker, in the time will realizing the miniaturization of motor with dust core stator, the part dimension that needs the attenuate fixture, promptly need with the thickness of dust core at least attenuate become 1/3, in dust core, possibly can't guarantee full intensity (becoming fragile).

Therefore, in order to ensure the intensity of dust core, must increase (thickening) component shape, the motor of the single-phase excitation type of a fixture of the pattern of wants.Yet in order fully effectively to utilize the magnetic force that is produced by coil, stator preferably becomes the prominent utmost point, but in the single-phase excitation of prominent utmost point magnetic core, does not produce rotating magnetic field, can't obtain making the torque of revolving part rotation.And, at patent documentation 2 to patent documentation 4 disclosed magnetic core shapes, the great majority around its magnetic flux on every side that produced by coil do not work as rotating torques, only can utilize the circumferential leakage flux that flows to the between cog up and down that alternately meshes as torque, thereby can't effectively utilize magnetic flux.

On the other hand, as the motor that does not use described permanent magnet, the SR motor of use SR (Switched reluctance) was arranged in the past.This SR motor is the motor that has utilized the reluctance torque that the variation of the magnetic resistance that is accompanied by rotation causes, the prominent utmost point of revolving part switches (switch) energising successively and makes this coil rotation for the coil of approaching fixture.Therefore, in this SR motor,, therefore have low-cost such advantage, and the demagnetization of the heat of magnet can not become problem, therefore compare, have the advantage that to carry out the running under the high temperature with described PM motor because revolving part do not use magnet.Yet this SR motor also is can't rotate under single-phase, and need be made as multilayer or heterogeneous structure.

Technical literature formerly

Patent documentation

Patent documentation 1: TOHKEMY 2009-43776 communique

Patent documentation 2: TOHKEMY 2006-333545 communique

Patent documentation 3: TOHKEMY 2007-325373 communique

Patent documentation 4: TOHKEMY 2009-142086 communique

Summary of the invention

The summary of invention

The present invention is the invention of making in view of above-mentioned situation, its purpose is to provide a kind of three-dimensional magnetic circuit that has, and can realize more effectively utilizing the DC brushless motor and the control method thereof of the motor of magnetic force, described three-dimensional magnetic circuit comprises single fixture and the solenoid with prominent utmost point.

DC brushless motor of the present invention possesses: fixture, and it possesses across single magnet exciting coil and in each main body of rotating the configuration of axial both sides; Revolving part, it is arranged on the inside of described fixture, each main body at described fixture forms first and second magnetic core, it is the projection of mutually different number that described first and second magnetic core has as the projection of magnetic pole, and described DC brushless motor is being actuating force with respect to the magnetic resistance change rate that flow, between described fixture and the described revolving part at the magnetic flux that produces around the described magnet exciting coil.And, the control method of DC brushless motor of the present invention is the electric conductor in ring-type is folded with the above-mentioned DC brushless motor that induction coil that rectifier cell forms is provided with respectively around the projection of second magnetic core a control method, the rectifier cell of described induction coil has sufficient rise time and wave height for connection, and will apply to described magnet exciting coil with the electric current as the pulse type of the corresponding polarity of the direction of rotation of target.The DC brushless motor and the control method thereof of such structure have three-dimensional magnetic circuit, and can more effectively utilize magnetic force, and this three-dimensional magnetic circuit comprises single fixture and the solenoid with prominent utmost point.

Above-mentioned and other purpose of the present invention, feature and advantage is by following detailed record and accompanying drawing and more clear and definite.

Description of drawings

Fig. 1 is the stereogram that the partial cut-out of the DC brushless motor of execution mode is represented.

Fig. 2 is the axis direction cutaway view of described DC brushless motor shown in Figure 1.

Fig. 3 is the axle right angle cutaway view of position of first magnetic core of described DC brushless motor shown in Figure 1.

Fig. 4 is the axle right angle cutaway view of position of second magnetic core of described DC brushless motor shown in Figure 1.

Fig. 5 is the stereogram of structure that is used for illustrating the actuating coil of described DC brushless motor shown in Figure 1.

Fig. 6 is the equivalent circuit diagram of described DC brushless motor shown in Figure 1.

Fig. 7 is the coordinate diagram of the relation that applies voltage and electric current of the rectifier cell of being located at described actuating coil in the expression described DC brushless motor shown in Figure 1.

Fig. 8 is the figure of the magnetic field analysis result that flows of the magnetic flux when described magnet exciting coil energising of expression described DC brushless motor shown in Figure 1.

Fig. 9 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 4, the second magnetic cores is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is the figure of result of calculation of 50% o'clock the inductance that is accompanied by rotation.

Figure 10 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 4, the second magnetic cores is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is the figure of result of calculation of 55% o'clock the inductance that is accompanied by rotation.

Figure 11 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 4, the second magnetic cores is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is the figure of result of calculation of 60% o'clock the inductance that is accompanied by rotation.

Figure 12 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 4, the second magnetic cores is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is the figure of result of calculation of 65% o'clock the inductance that is accompanied by rotation.

Figure 13 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 4, the second magnetic cores is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is the figure of result of calculation of 70% o'clock the inductance that is accompanied by rotation.

Figure 14 is that the number of magnetic poles of the expression revolving part and first magnetic core is 4, the number of magnetic poles of second magnetic core is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is under 60% the situation, in two magnetic cores of fixture, second magnetic core has moved ± figure that the inductance that is accompanied by rotation 11.25 ° the time changes with respect to the pole configuration of first magnetic core.

Figure 15 is that the number of magnetic poles of the expression revolving part and first magnetic core is 4, the number of magnetic poles of second magnetic core is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is under 60% the situation, in two magnetic cores of fixture, second magnetic core has moved ± figure that the inductance that is accompanied by rotation 16.9 ° the time changes with respect to the pole configuration of first magnetic core.

Figure 16 is that the number of magnetic poles of the expression revolving part and first magnetic core is 4, the number of magnetic poles of second magnetic core is 8, with respect to cycle of the magnetic pole of revolving part, magnet pole widths is under 60% the situation, in two magnetic cores of fixture, second magnetic core has moved ± figure that the inductance that is accompanied by rotation 25 ° the time changes with respect to the pole configuration of first magnetic core.

Figure 17 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 2, the second magnetic cores is the figure that 4 o'clock the inductance that is accompanied by rotation changes.

Figure 18 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 3, the second magnetic cores is the figure that 6 o'clock the inductance that is accompanied by rotation changes.

Figure 19 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 5, the second magnetic cores is the figure that 10 o'clock the inductance that is accompanied by rotation changes.

Figure 20 is that the number of magnetic poles of expression revolving part and first magnetic core is that the number of magnetic poles of 6, the second magnetic cores is the figure that 12 o'clock the inductance that is accompanied by rotation changes.

Figure 21 is the block diagram of a structure example of expression described DC brushless motor drive circuit shown in Figure 1.

Figure 22 is the figure that is used to illustrate the drive controlling action that is accompanied by rotation.

Figure 23 is the figure that is used to illustrate based on the starting method of the DC brushless motor of described drive circuit shown in Figure 21.

Embodiment

Below, based on accompanying drawing, a mode of enforcement of the present invention is described.Need to prove that the structure of mark prosign is represented same structure in each figure, suitably omits its explanation.And, in this manual, when general name, represent by the reference marks of having omitted additional character, when expression other structure, represent by the reference marks that has additional character.

Fig. 1 is the stereogram that the partial cut-out of the DC brushless motor 1 of execution mode is represented, Fig. 2 is the axis direction cutaway view of this DC brushless motor 1, Fig. 3 is the axle right angle cutaway view of position of first magnetic core 31 of this DC brushless motor 1, and Fig. 4 is the axle right angle cutaway view of position of second magnetic core 32 of this DC brushless motor 1.

This DC brushless motor 1 is a kind of following motor, the revolving part 4 of the internal rotor that comprises fixture 3 substantially, is provided with coaxially at inside and this fixture 3 of this fixture 3, rise and employ coil 5 (5a, 5b) with single magnet exciting coil 2, and carry out SR action, this SR action is an actuating force with the magnetic resistance change rate that flow, between fixture 3 and the revolving part 4 with respect to the magnetic flux that produces around the magnet exciting coil 2.And, in this DC brushless motor 1, in order to realize magnet exciting coil 2, and adopt following structure with described monomer.

At first, magnet exciting coil 2 is a monomer, when not producing rotating magnetic field, according to the difference of the anglec of rotation, does not under static state obtain torque sometimes, can't start voluntarily.Promptly, SR motor (Switched reluctance motor) is that actuating force is rotated with the magnetic resistance change rate, can't obtain torque at the rotary angle position place that does not have magnetic resistance change rate, in rotation, for example in rotation, even there is not the anglec of rotation of torque with the constant speed rotation, also can be rotated by inertia, but under static state, when not having the anglec of rotation of torque, can't start.

Therefore, the SR motor possesses the prominent utmost point (magnetic pole) at fixture and these both sides of revolving part.And in such DC brushless motor 1, revolving part 4 possesses: base portion 41 as usually; Extend and along circumferentially equally spaced forming to radial direction foreign side side from this base portion 41, and as a plurality of (being 4 in the example of Fig. 1 to Fig. 4) projection 42 of magnetic pole.

On the other hand, fixture 3 possesses first and second magnetic core 31,32 that is configured in the both sides of rotating shaft Z direction across circular magnet exciting coil 2, in described first and second magnetic core 31,32, is being different numbers as the number of the projection 311,321 of magnetic pole between described first magnetic core 31 and second magnetic core 32, can carry out the driving of described single magnet exciting coil 2 thus.For example, in the example of Fig. 1 to Fig. 4, first magnetic core 31 be and revolving part 4 with 4 of number, second magnetic core 32 is 2 times of first magnetic core 32 8.First and second magnetic core 31,32 possesses: form circular main body 312,322; Extend from this main body 312,322 square side in radial direction, and along a plurality of projection 311,321 of circumferential formation.

Therefore, just at two magnetic cores 31 of the both sides of the rotating shaft Z of magnet exciting coil 2 direction configuration, 32, in common blade tooth motor, alternately add along axially extended pawl utmost point systematicness ground and arrange, the flowing through revolving part of described magnetic flux and become diametric(al), with respect to this, in the present embodiment, projection 311 as magnetic pole, the 321st, from forming circular main body 312, the 322 prominent utmost points that square side is extended in radial direction, therefore described magnetic flux flows as shown in Figure 2, the homonymy of the revolving part 4 that is added by the projection 311 (321) from first magnetic core 31 (second magnetic core 32) leaks to the projection 321 (311) of second magnetic core 32 (first magnetic core 31).And, in described first magnetic core 31 and second magnetic core 32, the number difference of projection 311,321, thus, even in not producing the DC brushless motor 1 that constitutes by single magnet exciting coil 2 of rotating magnetic field, also can make the circumferential rotating torques of generation between any magnetic pole, thereby can carry out the driving of described single magnet exciting coil 2.

Like this, realize small-sized, the simple structure that constitutes by single magnet exciting coil 2 and fixture 3, and can carry out DC brushless motor 1 based on the driving of single-phase excitation.And, in order to carry out the SR action,, also the magnetic pole of fixture 3 can be made as the prominent utmost point even be single-phase excitation as described above, dash forward by this and extremely effectively utilize magnetic flux, thereby can realize high efficiency.In addition, this DC brushless motor 1 is owing to be simple structure, so productivity height, the SR motor is an actuating force with the magnetic resistance change rate of revolving part 4 and fixture 3 as described above, do not need permanent magnet, therefore and the required torque of the rotation that can obtain revolving part 4 is in the DC brushless motor in industrial and the people's livelihood with required power source, has the effect of the rare metal in the saving rare earth element magnet etc.

In table 1, show the DC brushless motor 1 of present embodiment and the comparative result of all types of motor of prior art.

[table 1]

[table 1]

That is, the DC brushless motor 1 of present embodiment does not need permanent magnet, carries out the action of the SR motor that can realize with the material of cheapness, and as blade tooth motor or claw-pole motor, magnet exciting coil is one and gets final product.Therefore, the DC brushless motor 1 of present embodiment can be simplified core or winding construction.

In addition, different by the number that makes the projection 311,321 in first and second magnetic core 31,32 as described above in the DC of present embodiment brushless motor 1, and can make the circumferential rotating torques of generation between any magnetic pole.And in the DC of present embodiment brushless motor 1, the number of the number of the projection 311 of first magnetic core 31 and the projection 42 of revolving part 4 is with number, can produce rotating torques relatively uniformly thus.

And, in this case, when the projection 42 of revolving part 4 stops at the centre position of projection 321 of second magnetic core 32, because the position difference of the projection 311 of first magnetic core 31, the starting difficulty that becomes.Therefore, around the projection 321 of second magnetic core 32, be provided as the actuating coil 5 of induction coil respectively.This actuating coil 5 is made of the electric conductor 51 of the ring-type that is folded with rectifier cell 52, and each rectifier cell 52 becomes opposite mode with the restriction of the energising direction that produced by rectifier cell 52 according to each adjacent magnetic pole and disposes respectively.

Situation such as Fig. 5 of this actuating coil 5 schematically show.Fig. 5 (A) is the figure of the basic structure of the above-mentioned actuating coil 5 of expression.Fig. 5 (B) illustrate each magnetic pole shown in this Fig. 5 (A) respectively individual volume around actuating coil 5 be equivalent on the beam in a side of the network of ladder shape situation with the circuit of rectifier cell 52 positive and negative alternates configuration.More specifically, for example, the circuit shown in Fig. 5 (B) is realized by the structure shown in Fig. 5 (C).Promptly, actuating coil 5 is as an actual structure example, it shown in Fig. 5 (C) the basket type structure of one, a circular conductor 511 and integral body are faced with each other for circular and closed circuit 512 that rectifier cell 52 positive and negative alternate ground are formed by connecting one by one, and utilize conductor pin 513 to be linked to be the ladder shape between two annulus.Fig. 5 (B) also can obtain and the equal effect of basic structure shown in Fig. 5 (A) even if the structure shown in this Fig. 5 (C) is shown.

Rectifier cell 52 is located in the closed circuit 512 of 31,32 of first and second magnetic cores.This is because have the exchange flux of the inside that connects revolving part 4 in 31,32 closed circuits that accompany 512 of first and second magnetic core, so produce induced electromotive force at this closed circuit 512.Therefore, when rectifier cell 52 being configured in circular conductor 511 sides, produce induced current, can't produce the motor force of the intention of present embodiment in closed circuit 512 sides.

The equivalent electric circuit of the DC brushless motor 1 of the present embodiment of Gou Chenging as shown in Figure 6 as described above.In Motor Control described later, under motor when beginning rotation such situation, when magnet exciting coil 2 that the higher current impulse of fast wave height of rise time is flow through, the Dui Ying line of magnetic induction is from first magnetic core 31 (second magnetic core 32) of fixture 3 with it, via revolving part 4, flow into second magnetic core 32 (first magnetic core 31).In this case, according in the prominent rectifier cell 52a that reels on extremely of second magnetic core 32, the polarity of 52b, on electric conductor 51a, the 51b of two kinds of actuating coil 5a, 5b, produce the induced electromotive force corresponding with the rate of change of this line of magnetic induction.So, actuating coil 5a, 5b are examples of induction coil.

At this, with semi-conductive PN junction is that basic rectifier cell 52a, 52b has the such characteristic of Fig. 7, therefore be the positive direction of rectifier cell 52a, 52b and when bigger in the polarity of induced electromotive force than threshold voltage (Vth), this rectifier cell 52a, 52b connect, and induce induced current at electric conductor 51a, 51b.If polarity is the opposite direction of rectifier cell 52a, 52b or for below this rectifier cell 52a, 52b specified, then this rectifier cell 52a, 52b keep the state of disconnection, do not produce induced current.

Therefore, as described above when magnet exciting coil 2 is flow through in the current impulse with sufficient rise time and wave height, induced current flows through the side of two kinds of actuating coil 5a, 5b, and the magnetic pole generation opposing magnetic field a side who is wound with this actuating coil 5a, 5b is significantly decayed the line of magnetic induction of inflow.On the other hand, induced current does not flow through the opposing party of two kinds of actuating coil 5a, 5b, can the line of magnetic induction that flow into not impacted.

At this, when the number of the projection 321 of second magnetic core 32 forms the multiple of number of projection 311 of first magnetic core 31, especially as shown in Figures 3 and 4,321 two of the projections of second magnetic core 32 are a pair of, with the projection 311 of first magnetic core 31 of correspondence is center and along the configuration of circumferentially staggering equably, can produce more uniform rotating torques thus.On the other hand, in this case, when the projection 42 of revolving part 4 and projection 311 arrangements of first magnetic core 31, promptly, when stopping at the centre position of projection 321 of described paired second magnetic core 32, the line of magnetic induction that flows into to the projection 42 of revolving part 4 from certain magnetic pole of first magnetic core 31 roughly along axially via this revolving part 4, separately flow into respect to the axle of projection 42 and two projections 321 of configuration equally spaced the starting difficulty that becomes.

Therefore, actuating coil 5 as described above is set, and utilize current impulse to carry out excitation with sufficient rise time and wave height, thus, circular current flows through the magnetic pole of the actuating coil side that rectifier cell 52 connected, the magnetic flux that induces is a described counter magnetic flux and not flowing into, and only the magnetic flux that keeps inducing on the magnetic pole of actuating coil side of the state that disconnects at rectifier cell 52 flows into.Certainly, when the polarity with current impulse is made as when opposite, the effect of two kinds of above-mentioned induction coils is alternately moved, the polarity of the current impulse by selecting starting, and can make the rotation starting of revolving part 4 along direction of rotation as target.

Like this, even stop in the projection 42 of revolving part 4 as described above under the situation of 321 of projections of second magnetic core 32, also can produce unequal magnetic field between a pair of projection 321 of the revolving part 4 and second magnetic core 32, the DC brushless motor 1 of present embodiment can make magnetic resistance change rate no longer constant.Like this, even if the combination of single magnet exciting coil 2 and fixture 4 also can realize the SR motor that can start voluntarily.And, actuating coil 5 is the basket type structure of one as described above, therefore under the state that the side with circular conductor 511 and closed circuit 512 these two ring bodies dismantles, this actuating coil 5 is embedded second magnetic core 32, afterwards, only engage with conductor pin 513 by ring body with a described side, just can be to these second magnetic core, 32 coiling actuating coils 5, assembling is easily.

In addition, in the DC of present embodiment brushless motor 1, as shown in Figure 1, described magnet exciting coil 2 forms by the conductor component of band shape is reeled along the mode of the rotating shaft Z direction of this magnet exciting coil 2 with its Width flatly.At this, when coil electricity,, therefore go up and produce eddy current usually at the face vertical (normal surface) with the magnetic line of force because coil is made of conductor, produce loss (loss) thus.Under the identical situation of magnetic flux density, the size of this eddy current and the area that intersects with the line of magnetic induction, the area of promptly vertical with the line of magnetic induction continuous face is proportional.Because the line of magnetic induction is in coil along axially, so area with face radially axial quadrature the conductor of eddy current and formation coil is proportional.Therefore, constituting thickness t that the conductor component of the band shape of magnet exciting coil 2 preferably will be radially forms below 1/10 with respect to the ratio t/W of width W.

By formation like this, can suppress described eddy current, thereby suppress heating.And banded conductor component can seamlessly be reeled, and therefore compares with the situation of the wire rod of coiling column shape, can increase current density, and also good from the heat radiation of conductor component inside.And, if the described thickness t of described conductor component be below the epidermal thickness with respect to the frequency of the alternating electromotive force of powering to this motor, then can further reduce eddy current loss.Need to prove, be ω at the angular frequency of alternating electromotive force, and the permeability of conductor component is μ, and when the conductance of conductor component was ρ, epidermal thickness δ was generally δ=(2/ ω μ ρ) ^1/2

In addition, in the DC of such structure brushless motor 1, preferably heat conduction member is filled in the gap that produces between two magnetic cores 31,32 of magnet exciting coil 2 and fixture 3.By formation like this, can to two magnetic cores, 31,32 conduction of surrounding this magnet exciting coil 2, can improve thermal diffusivity effectively with the heat that produces by magnet exciting coil 2 via described heat conduction member.

In addition, in the DC of such structure brushless motor 1, the inner surface of first magnetic core 31 of on the described rotating shaft Z direction and a square end portion this magnet exciting coil 2 opposed fixture 3 and on the zone that covers described each end, form abreast at least with the inner surface of opposed second magnetic core 32 in the opposing party end is preferred.This be because, when setting the condition (being that flat winding construction and width W are bigger than thickness t) of magnet exciting coil 2 as described above, first and second magnetic core 31,32 that covers as if the both ends of the surface up and down with magnet exciting coil 2 exists to tilt, then in fact the line of magnetic induction (magnetic line of force) of the inside by magnet exciting coil 2 especially near described both ends of the surface up and down not with rotating shaft Z direction almost parallel, therefore can't bring into play the effect of the described condition of having set magnet exciting coil 2 to greatest extent, above-mentioned such setting is in order to bring into play described effect to greatest extent.

The present application person carries out various changes to the depth of parallelism of the internal face of two magnetic cores 31,32 and has verified under the situation of distribution of the line of magnetic induction, for example, in the described depth of parallelism is 1/100 o'clock, the line of magnetic induction of the inside by magnet exciting coil 2 is parallel with rotating shaft Z direction, and be-1/10 or 1/10 o'clock in the described depth of parallelism, the line of magnetic induction and the rotating shaft Z direction of the inside by magnet exciting coil 2 are not parallel.Under such checking, parallel for the line of magnetic induction that makes the inside by magnet exciting coil 2, the absolute value of the described depth of parallelism is preferably below 1/50.

At this, consider because the gap of revolving part 4 and fixture 3 changed and the situation of magnetic circuit generation geometry deformation according to both having or not of magnetic pole.Yet, resolve according to the magnetic field that the present application person carries out, confirmed as shown in Figure 8 and brought the situation (can guarantee the situation parallel) of bigger variation can not for the mode of the line of magnetic induction that connects magnet exciting coil 2 with tape conductor.In Fig. 8, the projection 311,321 of fixture 3 is a fundamental form to the little Fig. 8 (A) in revolving part 4 side-prominent and described gaps all, magnetic field analysis result when the gap of a side shown in its Fig. 8 (B) becomes big, the magnetic field analysis result when two sides broaden shown in Fig. 8 (C).

In addition, in the DC of present embodiment brushless motor 1, first and second magnetic core 31,32 and revolving part 4 is preferably by by having dust core that isotropic iron-based soft magnetic powder constitutes, ferrite core on magnetic, and being formed by any that makes that soft magnetic alloy powder is dispersed in the magnetic core that the soft magnetic material in the resin constitutes.By formation like this, complicated about two magnetic cores of revolving part 3 and fixture 4 even hypothesis becomes, also can be shaped to best shape, therefore desirable magnetic characteristic can be obtained with comparalive ease, and desirable shape can be formed with comparalive ease.

Described soft magnetic powder is a strong magnetic metal powder, more specifically, the iron powder etc. that can list for example straight iron powder, iron(-)base powder (Fe-Al alloy, Fe-Si alloy, sendust, permalloy etc.) and noncrystalline powder and be formed with electric insulation epithelium such as the synthetic epithelium of phosphoric acid system on the surface.Described soft magnetic powder for example can carry out the method for corpusculed, iron oxide etc. is ground into after the powder its method of reducing waited make by utilizing atomization etc.

Such soft magnetic powder can with the mixing of nonmagnetic material powder such as monomer or described resin in use, ratio during mixing can be adjusted with comparalive ease, by this blending ratio of suitable adjustment, can make the magnetic characteristic of this core material realize desirable magnetic characteristic easily.From the viewpoint of cost degradation, constitute the material of two magnetic cores 31,32 of described fixture 3 and the material of revolving part 4 and be preferably same raw material.

In addition, in the DC of present embodiment brushless motor 1, the circumferential cross-section of at least one side's of first and second magnetic core 31,32 (being 31 in Fig. 1 and Fig. 2) main body 312 forms the L font.By formation like this, DC brushless motor 11 only embeds magnet exciting coil 2 by the inboard to the L word, just can assemble.

Next, the magnet pole widths of fixture 3 and revolving part 4 is described, promptly in projection 311,321; The optimum range of the circumferential lengths (=area) of this front end on the barrel surface of the track that 42 front end produces.The rate of change with respect to the anglec of rotation θ of revolving part 4 of torque F δ x (=N δ θ) that produces by the electric motor structure of present embodiment and inductance L according to the approximate calculation of model magnetic circuit shown below

Proportional.

[mathematical expression 1]

$F\·\mathrm{\δx}=N\·\mathrm{\δ\θ}=\mathrm{\ΔE}=\frac{\∂}{\∂\mathrm{\θ}}\left(\frac{1}{2}{L}_{\left(\mathrm{\θ}\right)}{I}^2\right)\·\mathrm{\δ\θ}=\frac{1}{2}{I}^2\frac{\∂L_{\left(\mathrm{\θ}\right)}}{\∂\mathrm{\θ}}\·\mathrm{\δ\θ}$

$\⇒\mathrm{Noc}\frac{\∂L_{\left(\mathrm{\θ}\right)}}{\∂\mathrm{\θ}}$

At this, used the fully little and line of magnetic induction in gap (g) between the magnetic pole of fixture 3 and revolving part 4 only by the such approximate model in described magnetic pole overlapping region each other.The inductance of the equivalent magnetic circuit of this electric motor structure of this situation and series connection magnetic resistance are inversely proportional, this series connection magnetic resistance is the magnetic resistance of connecting of the magnetic resistance between magnetic resistance and the revolving part 4 and second magnetic core 32 between first magnetic core 31 and the revolving part 4, therefore can obtain the approximate budgetary estimate formula of following formula.

[mathematical expression 2]

$L_{(\mathrm{\θ},\mathrm{\φ})}\∝\frac{1}{\frac{g_{\mathrm{upper}}}{S_{\mathrm{upper}\left(\mathrm{\θ}\right)}}+\frac{g_{\mathrm{lower}}}{S_{\mathrm{lower}(\mathrm{\θ},\mathrm{\φ})}}}\≈\frac{1}{g(\frac{1}{S_{\mathrm{upper}\left(\mathrm{\θ}\right)}}+\frac{1}{S_{\mathrm{lower}(\mathrm{\θ},\mathrm{\φ})}})}\∝\frac{S_{\mathrm{upper}\left(\mathrm{\θ}\right)}\×S_{\mathrm{lower}(\mathrm{\θ},\mathrm{\φ})}}{S_{\mathrm{upper}}\left(\mathrm{\θ}\right)+S_{\mathrm{lower}(\mathrm{\θ},\mathrm{\φ})}}$

S wherein _U/l: the overlapping area of the prominent utmost point of rotor and stator

ΔL≡L _max-L _min， $\frac{\mathrm{\ΔL}}{2L}\≡\frac{L_{\max }-L_{\min }}{L_{\max }+L_{\min }}[\%]$

At this, g _UpperBe that interval between the projection (magnetic pole) 42 of projection (magnetic pole) 311 of first magnetic core 31 and revolving part 4 is long, g _LowerBe that interval between the projection (magnetic pole) 42 of projection (magnetic pole) 321 of second magnetic core 32 and revolving part 4 is long, S _Upper(θ) be opposed faces overlapping area each other between the projection (magnetic pole) 42 of projection (magnetic pole) 311 of first magnetic core 31 and revolving part 4, S _Lower(θ) be opposed faces overlapping area each other between the projection (magnetic pole) 42 of projection (magnetic pole) 321 of second magnetic core 32 and revolving part 4.

That is, the overlapping area of magnetic pole becomes inductance L, and the size of torque is the maximum Lmax of this inductance L and the difference Δ L of minimum Lmin, can roughly estimate its size.

The total (ratio) of the circumferential magnet pole widths of revolving part shown in Fig. 9 to Figure 13 4 is respectively 50%, 55%, 60%, 65%, 70% o'clock of complete cycle, and actuating coil 5 is the variation of inductance (relative value) of the anglec of rotation of the revolving part 4 of on-state (2 polarity) with respect to two side's off-states (promptly conventional SR action) and a side.Need to prove, described Fig. 9 to Figure 13 just as described above, revolving part 4 is 4 utmost points, first magnetic core 31 is 4 utmost points, when second magnetic core 32 is 8 utmost points, the circumferential magnet pole widths of 50%, the second magnetic core 32 that adds up to complete cycle of the circumferential magnet pole widths of first magnetic core 31 add up to 50% of complete cycle, and the magnetic pole of second magnetic core 32 moves 22.5 ° from first magnetic core 31.In described each figure, the expansion of the complete cycle (360 °) of the barrel surface of the described track of figure (A) expression first magnetic core 31, the expansion of figure (B) expression revolving part 4, the expansion of figure (C) expression second magnetic core 32, and the inductance of 180 ° of amounts of figure (D) expression is with respect to the variation of the anglec of rotation of described revolving part 4.Among the figure (D), solid line is the situation of conventional state, the situation when dotted line is the starting of just changeing, the situation when the single-point line is the starting of reversing.Among above-mentioned Fig. 3 and Fig. 4, the total of the circumferential magnet pole widths of first and second magnetic core 31,32 is represented 50% of complete cycle, and in this case, central angle becomes 45 ° and 22.5 ° respectively.And the total of the circumferential magnet pole widths of revolving part 4 is represented 60% of complete cycle, and in this case, central angle becomes 54 °.

In order to obtain torque, need make actuating coil 5 be the state inductance variation down that disconnects of two sides greatly, and, rotation when starting in order to make is started to any direction, near the extreme value of inductance, a side that need make actuating coil 5 is that the inductance of on-state has the slope (generation starting torque) that increases (subtracting) variation.Magnet pole widths (ratio) at revolving part shown in Figure 94 is 50% o'clock, (0 °, 90 °, 180 ° these each situations of the anglec of rotation) become above-mentioned such near the maximum, but (45 °, 135 ° these each situations of the anglec of rotation) do not obtain starting torque near minimum.On the other hand, be 70% o'clock in the magnet pole widths (ratio) of revolving part shown in Figure 13 4, though can obtain starting torque near minimum, actuating coil 5 is that the inductance changes delta L under two side's off-states reduces.

That is, exist in the inductance when SR drives greatly and minimum these two kinds of balance points, each balance point is equivalent to magnetic pole opposed " point of safes " and magnetic pole become each other mutually different " point of instability " respectively.Therefore short of unusual especially external force works, and when static, revolving part just can not fall within the latter usually, even under the magnet pole widths of revolving part is 50% condition, starts also not difficult.Yet, motor load is more special, though exist revolving part to be still in the possibility of the latter's balance point, but, can be that 55%, 60% and 65% calculated example illustrates also to the situation of the positive and negative any direction starting magnet pole widths (ratio) by revolving part 4 by suitably using second magnetic core 32.Yet when described magnet pole widths was excessive, the torque that SR drives was also lost.

Therefore, controlled viewpoint from torque and starting rotation, in the barrel surface of the track that magnetic pole (projection 42) front end of revolving part 4 produces, the ratio η of the circumferential lengths of this front end is preferably 50%≤η≤65% (that is, the ratio at the interval of 42 of projections is below 50% and more than 35%).By formation like this, DC brushless motor 1 can produce big torque, and can start from stop position arbitrarily.

On the other hand, in Figure 14 to Figure 16, the magnet pole widths of revolving part 4 and above-mentioned Figure 11 are shown respectively similarly are fixed as 60%, the pole configuration of second magnetic core 32 that makes fixture 3 with respect to the magnetic pole of first magnetic core 31 and be changed to ± 11.25 ° (magnet pole widths is 50%, count 22.5 ° with central angle, adjacent), ± 16.9 °, ± each result of variation inductance 25 ° (bigger), that be accompanied by rotation than uniformly-spaced.In described each figure, with Fig. 9 to Figure 13 similarly, the expansion of the complete cycle (360 °) of the barrel surface of the described track of figure (A) expression first magnetic core 31, the expansion of figure (B) expression revolving part 4, the expansion of figure (C) expression second magnetic core 32, and the inductance of 180 ° of amounts of figure (D) expression is with respect to the variation of the anglec of rotation of described revolving part 4.

Consequently, under the situation of the adjacent Figure 14 of a pair of second magnetic core 32, though the inductance under the state that actuating coil 5 is two sides to be disconnected changes greatly, revolving part 4 is under near the state the centre that stops at this a pair of second magnetic core 32, and is uncertain to which side starting.And, under the situation of the deviation of shown in Figure 15 ± 16.9 °, to compare with the situation of the deviation of shown in Figure 11 ± 22.5 °, a side of actuating coil 5 is that the slope that changes of the increasing of inductance (subtracting) of on-state is mild.And, under the situation of the deviation of shown in Figure 16 ± 25 °, compare with the situation of the deviation of shown in Figure 11 ± 22.5 °, be under the on-state in a side of actuating coil 5, the width that does not produce starting torque is big.Therefore, to the condition of the deviation of second magnetic core 32 shown in Figure 16, do not show inductance behavior than the situation excellence of Figure 11 at described Figure 14, and ± 22.5 ° deviation becomes optimum condition.

In addition, in Figure 17 to Figure 20, at first magnetic core 31: the relation of the number of magnetic poles of 4: the second magnetic cores 32 of revolving part is maintained under the situation of 1:1:2 as described above, the send as an envoy to behavior of the inductance of number of poles when changing of performance.As described above, as first magnetic core 31: the number of magnetic poles separately of 4: the second magnetic cores 32 of revolving part, Figure 17 represents the situation of 2:2:4, and Figure 18 represents the situation of 3:3:6, and Figure 19 represents the situation of 5:5:10, and Figure 20 represents the situation of 6:6:12.With the situation of Figure 11 similarly, each of the circumferential magnet pole widths of first magnetic core 31, revolving part 4 and second magnetic core 32 amounts to and is respectively 50%, 60% and 50% of complete cycle.And, in described each figure, with Fig. 9 to Figure 13 similarly, the expansion of the complete cycle (360 °) of the barrel surface of the described track of figure (A) expression first magnetic core 31, the expansion of figure (B) expression revolving part 4, the expansion of figure (C) expression second magnetic core 32, and figure (D) expression inductance is with respect to the variation of the anglec of rotation of described revolving part 4.

In each result of Figure 17 to Figure 20, owing to equating therefore all there is not big difference geometrically.In the parsing of this approximate model (line of magnetic induction only the overlapping area by magnetic pole approximate), torque and number of poles are proportional, but in fact, because existence is to the leakage flux in the zone of the depression of magnetic pole and magnetic pole, there is the number of poles that becomes torque the best though therefore be speculated as, but, therefore there is not general rule owing to depend on concave shape, size.

Figure 21 is a block diagram of representing a structure example of the drive circuit 71 of the DC brushless motor 1 that constitutes as described above and regenerative circuit 72.Drive circuit 71 possesses bridge circuit and reactor L1 and constitutes, and this bridge circuit possesses reverse parallel connection diode D1～D4 that switch element Tr1～Tr4 and surge thereof absorb usefulness and forms, to described magnet exciting coil 2 output start pulse described later and driving pulses.This drive circuit 71 is a power circuit with the capacitor 74 that secondary cell 73 reaches the stable usefulness that is connected in parallel with secondary cell 73, by not shown drive control circuit.Between power line 75,76, be connected with the series circuit of switch element Tr1, Tr2 and the series circuit of switch element Tr3, Tr4 (described series circuit is connected in parallel with each other), switch element Tr1, Tr2 from described secondary cell 73 and capacitor 74; Each tie point of Tr3, Tr4 becomes the output taking-up end to described magnet exciting coil 2.Take out between side of end and the magnet exciting coil 2 in described output and to be folded with reactor L1.

And, in this drive circuit 71, by utilizing described diagram abridged Drive and Control Circuit that switch element Tr1, Tr4 are connected and can making revolving part 4, by utilizing described diagram abridged Drive and Control Circuit that switch element Tr3, Tr2 are connected and revolving part 4 being rotated to other direction to direction rotation.By controlling the duty ratio of described switch element Tr1～Tr4, adjust the wave height value of the driving pulse that applies to magnet exciting coil 2, thereby adjust the wave height value of exciting current.And, by utilizing described diagram abridged Drive and Control Circuit switch element Tr2, Tr4 are connected, and can be with the two-terminal ground connection of magnet exciting coil 2.In order to carry out the control of such switch element Tr1 to Tr4, revolving part 4 at DC brushless motor 1 is provided with not shown encoder, described Drive and Control Circuit is controlled each switch element Tr1～Tr4 as described later according to by the detected rotary angle position of described encoder.Switch element Tr1～Tr4 possesses IGBT, MOS-FET constant power transistor.Need to prove, also can be connected capacitor in parallel with reactor L1.And under the situation of regenerating, reactor L1 also can be contained in the inductance L of DC brushless motor 1 side.

The full-wave rectifying circuit that regenerative circuit 72 possesses reactor L2 and is made of diode D11～D14 is to capacitor 77 output regenerated electric powers.Described reactor L2 constitutes the reactor L1 and the current transformer 78 of described drive circuit 71 sides.And, at revolving part 4 by and when rotating from the power of outside, perhaps when the deceleration of usefulness such as stopping, by supplying with exciting current to magnet exciting coil 2 from drive circuit 71, and produce magnetic field at reactor L1, under this state, inductance changes if be accompanied by the rotation of revolving part 4, then produce inverse electromotive force at described reactor L1, L2 accumulates regenerative current to capacitor by reactor.This is the mechanism of the summary of regeneration, more specifically, by switch element Tr1～Tr4 described exciting current is carried out switch, by adjusting the opportunity of this switch, and make magnet exciting coil 2 and reactor L1 become resonance state, its resonance current is taken out by reactor L2, and carries out rectification and can obtain regenerative voltage by diode bridge.

And the driving situation of the described Drive and Control Circuit under the conventional rotation status as shown in figure 22.When Figure 22 (B) is illustrated in and quickens from described Drive and Control Circuit to switch element Tr1, Tr4; The driving pulse that Tr3, Tr2 apply.And, the variation of the described inductance L when Figure 22 (A) represents such driving.When quickening, described inductance L become minimum Lmin near, driving pulse is connected, become maximum Lmax near, driving pulse is disconnected.

Use drive circuit 71 as described above,, the starting method of present embodiment is described with reference to Figure 23.Figure 23 represents variation inductance, and is same with above-mentioned Figure 11 (D).That is, first magnetic core 31 and revolving part 4 are 4 utmost points, and second magnetic core 32 is 8 utmost points, the magnet pole widths of first magnetic core 31 is 50%, the magnet pole widths of revolving part 4 is that the magnet pole widths of 60%, the second magnetic core 32 moves 22.5 ° for the magnetic pole that amounts to 50%, the second magnetic core 32 from first magnetic core 31.

As described above, the rotary angle position of revolving part 4 is by detections such as encoders, and described Drive and Control Circuit responds the testing result of rotation beginning angle, according to the angular regions W1～W4 of 4 following kinds, as shown in table 2, carry out the Current Control in start pulse and the driving pulse.The situation that Figure 23 supposition makes motor drive to positive veer (coordinate diagram from left to right), when reverse directions drives, the distribution of described angular regions W1～W4 is also opposite.

[table 2]

Table 2 is conceived to from the point of the angular regions starting with each inductance characteristic of described Figure 23, and the expression starting is arrived the waveform of conventional rotation then to quickening.In this table 2, by will during the waveform represented of T0, T1, T2, T3 with make the waveform combination of its polarity inversion, and can realize torque control and speed control for all running patterns.But, even in described angular regions W1～W4 according to from the weight of starting of which position or load etc., and import identical start pulse or driving pulse, in fact response on the other side is also different, therefore the example shown in this table 2 is nothing but target, described Drive and Control Circuit responds the testing result of described encoder, and controls the wave height value of start pulse number or driving pulse successively.In table 2,

And

Inductance when representing the starting of a pair of second magnetic core 32 changes,

The magnetic core of expression direction of rotation upstream side (in Figure 23, starting (+)),

The magnetic core in expression direction of rotation downstream (in Figure 23, starting (-)).

At first, in the magnetic pole of revolving part 4 and angular regions W2 that the magnetic pole of first magnetic core 31 relatively separates, in the magnetic core of direction of rotation upstream side, inductance increases (just), in the magnetic core in downstream, inductance reduces (bearing), so drive circuit 71 applies start pulse and the driving pulse shown in the classification 3 of table 2 to magnet exciting coil 2, thus, DC brushless motor 1 is rotated starting.That is, by the start pulse shown in the T1 between period of output, the direction of rotation upstream side in a pair of actuating coil 5 disconnects, and the downstream is connected, and thus, utilize the magnetic pole of this upstream side of second magnetic core 32 to attract revolving part 4, and DC brushless motor 1 is just changeing starting.Then, as during shown in the T2, before reaching constant speed, export the driving pulse of big wave height value, and DC brushless motor 1 quickens, and when reaching described constant speed, transition is conventional rotation, as during shown in the T3, the wave height value of driving pulse reduces and DC brushless motor 1 is kept this routine rotation.In described angular regions W2, especially roughly become in the angular regions of zero W5 at the inductance of the magnetic core in direction of rotation downstream, shown in the classification 4 of table 2, can reduce described during the start pulse of T1.

On the other hand, at the magnetic pole of revolving part 4 relatively among the angular regions W3 near the magnetic pole of first magnetic core 31, in the magnetic core of direction of rotation upstream side, inductance reduces (bearing), in the magnetic core in downstream, inductance increases (just), so drive circuit 71 applies start pulse and the driving pulse shown in the classification 2 of table 2 to magnet exciting coil 2, thus, DC brushless motor 1 is rotated starting.Promptly, by the start pulse of the reversed polarity shown in the T1 ' between period of output, the direction of rotation downstream in a pair of actuating coil 5 disconnects, and upstream side is connected, the magnetic pole in this downstream by second magnetic core 32 attracts revolving part 4 thus, and DC brushless motor 1 is just changeing starting.Then, as during T2 to during shown in the T3, the wave height value of the driving pulse of control positive polarity, thus exciting current is become little state from big State Control, DC brushless motor 1 is to routine rotation transition, and keeps.

With respect to this, at the magnetic pole of revolving part 4 when the angular regions W4 of the magnetic pole of having crossed first magnetic core 31 starts, in the magnetic core of direction of rotation upstream side, inductance is roughly zero, in the magnetic core in downstream, inductance reduces (bearing), so drive circuit 71 applies inversion pulse, start pulse and the driving pulse shown in the classification 1 of table 2 to magnet exciting coil 2, thus, DC brushless motor 1 is rotated starting.That is, during T0, direction of rotation upstream side in a pair of actuating coil 5 disconnects, the downstream is connected, thus to the poles attract revolving part 4 of this upstream side of second magnetic core 32, and DC brushless motor 1 starting of reversing, thereby it is involutory to carry out the position.And, during T1 ', direction of rotation downstream in a pair of actuating coil 5 disconnects, upstream side is connected, thus to the poles attract revolving part 4 in this downstream of second magnetic core 32, and DC brushless motor 1 is just changeing starting.After, about during T2, T3, control exciting current similarly.

When opposite spin, in above-mentioned angular regions W1～W5, can be with the polarity of current waveform of the Current Control table 2 of counter-rotating.And, serve as basic with action as described above, by the Current Control sequential of following such application, can tackle various demand.For example, when the rotation starting, to do one's utmost to improve under the situation of electrical efficiency, the angular regions that starting circuit 71 makes revolving part 4 is when the angular regions W1 of Figure 23 begins to rotate, and the electric current of the acceleration by T2 during directly making flows through magnet exciting coil 2, and can make the 1 rotation starting of DC brushless motor.Perhaps electrical efficiency is not enough, and in rotation, will do one's utmost to prolong torque generation time with respect to the motor of load torque the time, in the angular regions W2 of Figure 23, shown in T1 during the classification 3 of table 2, make the pulse current of rectifier cell 52 connections of actuating coil 5 flow through magnet exciting coil 2, in angular regions W3, the pulse current that such rectifier cell that makes actuating coil 5 52 is connected shown in the T1 ' during the classification 1 of table 2 flows through magnet exciting coil 2, can prolong the torque generation time of DC brushless motor 1 thus.

As previously discussed, control method according to the DC brushless motor 1 of present embodiment, as T1 during the table 2, shown in the T1 ', because actuating coil 5a, the rectifier cell 52a of 5b, 52b has sufficient rise time and wave height for connection, and will apply to described magnet exciting coil 2 with electric current as the pulse type of the corresponding polarity of the direction of rotation of target, revolving part 4 is started to the target direction of rotation, therefore as described above, even the projection 42 of revolving part 4 stops at the centre position of the projection 321 of second magnetic core 32, also can make 1 starting of DC brushless motor reliably.

In addition, in the control method of the DC of present embodiment brushless motor 1, and during the rotation of the position that the inductance characteristic that the rotary angle position of this revolving part 4 produces between fixture 3 and this revolving part 4 does not increase with respect to the target direction of rotation of revolving part 4, shown in T0 during the table 2, the electric current that is used to make described revolving part 4 be inverted to the angle that increases to target direction of rotation inductance flows to magnet exciting coil 2 in advance, when arriving the angle that increases to target direction of rotation inductance, apply described during T1, the electric current of the pulse type shown in the T1 ', therefore, even the stop position of revolving part 4 is the positions that can't obtain starting torque with respect to the target direction of rotation, also can make DC brushless motor 1 reliably to original target direction of rotation starting.

In addition, after described revolving part 4 begins rotation, only in the angular regions W1 that increases to target direction of rotation inductance, with the electric current of direction of rotation same-sign (be positive current during positive rotation, negative rotation is a negative current when changeing) flow through magnet exciting coil 2, and control its wave height value by the duty ratio of switch element Tr1～Tr4, thus, revolving part 4 is kept rotary speed to the target direction of rotation, maybe can control rotary speed arbitrarily.

In addition, rectifier cell 52a, 52b with actuating coil 5a, 5b have sufficient rise time and the wave height of connecting usefulness, and the electric current that makes the polarity corresponding with the target direction of rotation flows through described magnet exciting coil 2, thus, in the DC of present embodiment brushless motor 1, can carry out the high speed rotating control that the rated speed under the underload torque was controlled or surpassed in the torque corresponding with load torque.

In addition, preferably,, and in the DC of present embodiment brushless motor 1, torque can be improved this a plurality of multiple by described fixture 3 is stacked a plurality of along rotating shaft Z direction.And, owing to be a plurality of, stagger equably by the phase angle that makes first and second magnetic core 31,32, and in the DC of present embodiment brushless motor 1, can reduce cogging torque.

This specification discloses the technology of various forms as described above, but major technology wherein is summarized as follows.

The DC brushless motor of one form possesses: the fixture with single magnet exciting coil; Be arranged on the revolving part of the inside of described fixture coaxially, to be actuating force with respect to the magnetic resistance change rate that flow, between described fixture and the described revolving part at the magnetic flux that produces around the described magnet exciting coil, wherein, described revolving part possesses: base portion; Extend and along circumferentially equally spaced forming to radial direction foreign side side from described base portion, and as a plurality of projections of magnetic pole, described fixture possesses: circular described magnet exciting coil; First and second magnetic core, they have and are configured in the axial both sides of rotation across described magnet exciting coil, and form circular main body and extend from described main body square side in radial direction, a plurality of along circumferential formation, and as the projection of magnetic pole, the bump count of described first magnetic core and second magnetic core is different.

The DC brushless motor of such structure is the SR motor, possesses: the fixture with magnet exciting coil; Be arranged on the revolving part of for example internal rotor of the inside of described fixture coaxially, being actuating force with respect to magnetic resistance change rate that flow, between described fixture and the described revolving part at the magnetic flux that produces around the described magnet exciting coil.

And described magnet exciting coil is single coil, adopts following structure.That is, the DC brushless motor of said structure possesses the prominent utmost point (magnetic pole) at fixture and these both sides of revolving part, and revolving part possesses: base portion as usually; Extend and along circumferentially equally spaced forming to radial direction foreign side side from this base portion, and a plurality of projections as magnetic pole, and fixture is in first and second magnetic core that is being configured in the axial both sides of rotation across circular magnet exciting coil, is being different numbers as the number of the projection of magnetic pole between first magnetic core and second magnetic core.

Therefore, two magnetic cores of the rotation at magnet exciting coil of structure like this axial both sides configuration, in common SR motor, alternately add along axially extended pawl utmost point systematicness ground and arrange, the flowing through revolving part of described magnetic flux and become diametric(al), with respect to this, in the DC of such structure brushless motor, projection as magnetic pole is from forming the circular main body prominent utmost point that square side is extended in radial direction, therefore the homonymy of the revolving part that added by the projection from first magnetic core (second magnetic core) of flowing of described magnetic flux leaks to the projection of second magnetic core (first magnetic core).And in described first magnetic core and second magnetic core, the number difference of projection thus, produces circumferential rotating torques between arbitrary magnetic pole, and therefore, the DC brushless motor of such structure can carry out the driving of single coil.Thus, the DC brushless motor of such structure has three-dimensional magnetic circuit, and can more effectively utilize magnetic force, and this three-dimensional magnetic circuit comprises single fixture and the solenoid with prominent utmost point.

In addition, in another form, in above-mentioned DC brushless motor, the projection of described first magnetic core forms with the number identical with the projection of revolving part, the projection of described second magnetic core forms with 2 times number of the projection of revolving part, by the electric conductor in ring-type be folded with induction coil that rectifier cell forms be separately positioned on described second magnetic core projection around, described rectifier cell is so that the restriction of the energising direction that is produced by this rectifier cell becomes opposite mode according to each adjacent magnetic pole disposes.

The number of the number of the projection of the DC brushless motor of such structure by making first magnetic core and the projection of revolving part is mutually the same, and can produce rotating torques relatively uniformly.And, by second magnetic core is formed as described above, between adjacent induction coil, become in the other direction at the voltage that induction coil induces by the start pulse that applies to magnet exciting coil, in a side induction coil, rectifier cell is connected and circular current flows magnetic flux is offset (counter magnetic flux), and in the opposing party's induction coil, rectifier cell disconnects and circular current does not flow, therefore, magnetic flux keeps remaining untouched.Therefore,, between the projection of the second adjacent magnetic core, also produce unequal magnetic field, can make the variation of magnetic resistance no longer constant even the DC brushless motor of such structure stops at revolving part under the situation between the projection of second magnetic core.Like this, according to such structure, even the combination of single magnet exciting coil and fixture also can realize the SR motor that can start voluntarily.

In addition, in another form, in above-mentioned DC brushless motor, the projection of described second magnetic core is a pair of with two, and is center and along the configuration of circumferentially staggering equably with the projection of first magnetic core of correspondence.

The DC brushless motor of such structure disposes with respect to first magnetic core as described above by the projection with second magnetic core, and can produce more uniform rotating torques.

In addition, in another form, in above-mentioned DC brushless motor, in the barrel surface of the track of the projected front ends of described revolving part, the circumferential lengths of this front end (=area) is more than 50% and 65% following (that is being spaced apart below 50% and more than 35% between projection).

The DC brushless motor of such structure forms as described above by the projection with revolving part, and can produce big torque.

In addition, in another form, in above-mentioned DC brushless motor, described magnet exciting coil forms by the conductor component of band shape is reeled along the axial mode of the rotation of this magnet exciting coil with its Width.

The DC brushless motor of such structure is by forming magnet exciting coil as described above, and suppresses the eddy current that produces because of magnet exciting coil, thereby can suppress heating.And banded conductor component can seamlessly be reeled, and therefore the DC brushless motor of such structure is compared with the situation of the wire rod of coiling column shape, can increase current density, and also good from the heat radiation of conductor component inside.

In addition, in another form, in above-mentioned DC brushless motor, the electric conductor in the described induction coil is the basket type structure of one, possesses: extend and at the pillar of the both sides configuration of the projection of described each second magnetic core along the rotating shaft direction; Combine respectively with the two ends of described pillar, and at two ring bodies of configuration up and down of described projection, described rectifier cell is located in the ring body between first and second magnetic core, surrounds around described ring body will each magnetic pole.

The DC brushless motor of such structure is because induction coil is the basket type structure of one, therefore after under with the state of a side ring body dismounting, this induction coil being embedded second magnetic core, only engage with pillar by ring body with a described side, just can be to this second magnetic core coiling induction coil, its assembling is easily.

In addition, in another form, in above-mentioned DC brushless motor, described first and second magnetic core and revolving part be the dust core that is made of iron-based soft magnetic powder, ferrite core, and by making soft magnetic alloy powder be dispersed in the magnetic core that the soft magnetic material in the resin constitutes any.

The DC brushless motor of such structure since with first and second magnetic core and revolving part by above-mentioned any forms, therefore described first and second magnetic core and revolving part can be shaped to the arbitrary shape of the best and complexity.

In addition, in another form, in above-mentioned DC brushless motor, that described fixture is stacked a plurality of along the rotating shaft direction.

The DC brushless motor of such structure can improve torque a plurality of multiples.And the DC brushless motor of such structure staggers by the phase angle that makes first and second magnetic core equably because these are a plurality of, can make torque approaching equably.

In addition, in another form, in above-mentioned DC brushless motor, the circumferential cross-section of at least one side's of described first and second magnetic core main body forms the L font.

The DC brushless motor of such structure only embeds magnet exciting coil by the inboard to the L word, just can carry out its assembling.

In addition, in another form, the control method of DC brushless motor is the control method of above-mentioned any DC brushless motor, wherein, the rectifier cell of described induction coil has sufficient rise time and wave height for connection, and will apply to described magnet exciting coil with the electric current as the pulse type of the corresponding polarity of the direction of rotation of target, described revolving part is started to the target direction of rotation.

In the control method of the DC brushless motor of such structure,, also can start reliably even the projection of revolving part stops at the centre position of the projection of second magnetic core as described above.

In addition, in another form, in the control method of above-mentioned DC brushless motor, and during the rotation of the position that the inductance characteristic that the rotary angle position of described revolving part produces between described fixture and this revolving part does not increase with respect to the target direction of rotation of revolving part, the electric current that is used to make described revolving part be inverted to the angle that increases to target direction of rotation inductance flows to described magnet exciting coil in advance, when arriving the angle that increases to described target direction of rotation inductance, apply the electric current of described pulse type.

In the control method of the DC brushless motor of such structure, even the stop position of revolving part is the position that can't obtain starting torque with respect to the target direction of rotation, in case to driving in the other direction, after obtaining starting torque, also can drive, therefore can start more reliably to original target direction of rotation.

In addition, in another form, in the control method of above-mentioned DC brushless motor, after described revolving part begins rotation, only at inductance in the angular regions that described target direction of rotation increases, making the electric current with the direction of rotation same-sign (is positive current during positive rotation.Negative rotation is a negative current when changeing) flow through described magnet exciting coil, thus, described revolving part is kept rotary speed to described target direction of rotation.

In addition, in another form, in the control method of above-mentioned DC brushless motor, the rectifier cell of described induction coil has sufficient rise time and wave height for connection, and make the electric current of the polarity corresponding flow through described magnet exciting coil with the target direction of rotation, thus, can carry out the torque corresponding control and surpass arbitrary control in the high speed rotating control of rated speed of underload torque with load torque.

The application to be willing to the special 2010-250843 of hope based on Japan's patent of filing an application on November 9th, 2010, and its content is quoted in the application.

In order to show the present invention, above-mentioned the present invention has been described suitably and fully with reference to accompanying drawing and by execution mode, but has will be appreciated that the situation that those skilled in the art can easily change and/or improve above-mentioned execution mode.Therefore, alter mode that those skilled in the art implement or mode of ameliorating only otherwise break away from the rights protection scope of the scope record of claims just should be interpreted as this alter mode or this mode of ameliorating to be contained in the rights protection scope of claims.

Industrial utilizability

According to the present invention, can provide a kind of DC brushless motor.

Claims (13)

1. DC brushless motor is characterized in that possessing:

Fixture with single magnet exciting coil;

Be arranged on the revolving part of the inside of described fixture coaxially,

Described revolving part possesses: base portion; Extend and along circumferentially equally spaced forming to radial direction foreign side side from described base portion, and as a plurality of projections of magnetic pole,

Described fixture possesses: circular described magnet exciting coil; First magnetic core and second magnetic core, they have and are configured in the axial both sides of rotation across described magnet exciting coil, and form circular main body and extend from described main body square side in radial direction, and are a plurality of along circumferential formation, and as the projection of magnetic pole,

The bump count of described first magnetic core and second magnetic core is different,

Being actuating force with respect to magnetic resistance change rate that flow, between described fixture and the described revolving part at the magnetic flux that produces around the described magnet exciting coil.

2. DC brushless motor according to claim 1 is characterized in that,

The projection of described first magnetic core and the projection of revolving part are with number,

The projection of described second magnetic core is 2 times a number of the projection of revolving part,

By the electric conductor in ring-type be folded with induction coil that rectifier cell forms be separately positioned on described second magnetic core projection around,

Described rectifier cell is so that the restriction of the energising direction that is produced by this rectifier cell becomes opposite mode according to each adjacent magnetic pole disposes.

3. DC brushless motor according to claim 2 is characterized in that,

The projection of described second magnetic core is a pair of with two, and is center and along the configuration of circumferentially staggering equably with the projection of first magnetic core of correspondence.

4. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

In the barrel surface of the track that the projected front ends by described revolving part realizes, the circumferential lengths of this front end is more than 50% and below 65%.

5. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

Described magnet exciting coil forms by the conductor component of band shape is reeled along the axial mode of the rotation of this magnet exciting coil with its Width.

6. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

Electric conductor in the described induction coil is the basket type structure that possesses the one of pillar and two ring bodies, this pillar extends along the rotating shaft direction, and in the both sides configuration of the projection of each described second magnetic core, these two ring bodies combine respectively with the two ends of described pillar, and configuration up and down in described projection

Described rectifier cell is located in the ring body between first magnetic core and second magnetic core, and described ring body will surround around each magnetic pole.

7. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

Described first magnetic core and second magnetic core and revolving part are the dust core that is made of iron-based soft magnetic powder, ferrite core and by making soft magnetic alloy powder be dispersed in the magnetic core that the soft magnetic material in the resin constitutes any.

8. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

Described fixture is stacked a plurality of along the rotating shaft direction.

9. according to claim 2 or 3 described DC brushless motors, it is characterized in that,

The circumferential cross-section of at least one side's of described first magnetic core and second magnetic core main body forms the L font.

10. the control method of a DC brushless motor is the control method of claim 2 or 3 described DC brushless motors, it is characterized in that,

The rectifier cell of described induction coil has sufficient rise time and wave height for connection, and will apply to described magnet exciting coil with the electric current as the pulse type of the corresponding polarity of the direction of rotation of target, described revolving part is started to the target direction of rotation.

11. the control method of DC brushless motor according to claim 10 is characterized in that,

And during the rotation of the position that the inductance characteristic that the rotary angle position of described revolving part produces between described fixture and this revolving part does not increase with respect to the target direction of rotation of revolving part, the electric current that is used to make described revolving part be inverted to the angle that increases to target direction of rotation inductance flows to described magnet exciting coil in advance, arrive after the angle that described target direction of rotation inductance increases, applying the electric current of described pulse type.

12. the control method of DC brushless motor according to claim 10 is characterized in that,

After described revolving part begins rotation, only in the angular regions that increases to described target direction of rotation inductance, make the electric current with the direction of rotation same-sign flow through described magnet exciting coil, thus, described revolving part is kept rotary speed to described target direction of rotation.

13. the control method of DC brushless motor according to claim 10 is characterized in that,

The rectifier cell of described induction coil has sufficient rise time and wave height for connection, and make the electric current of the polarity corresponding flow through described magnet exciting coil with the target direction of rotation, thus, can carry out the torque control corresponding with load torque reaches above the arbitrary control in the high speed rotating control of the rated speed under the underload torque.

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